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2020: day07: memoize part 1

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This commit is contained in:
Antoine Martin 2020-12-07 15:27:31 +01:00
parent bb5e0c9c9e
commit 213e074e6b
1 changed files with 23 additions and 10 deletions
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31
aoc2020/src/day07.rs
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@ -28,9 +28,11 @@ fn part1(input: &str) -> aoc::Result<usize> {
.map(|bag_rule| (bag_rule.color.clone(), bag_rule.clone()))
.collect();
let mut memoized = HashMap::new();
Ok(bag_rules
.iter()
.filter(|bag| bag.can_contain("shiny gold", &bag_rules_map))
.filter(|bag| bag.can_contain("shiny gold", &bag_rules_map, &mut memoized))
.count())
}
@ -59,17 +61,28 @@ struct BagRule {
}
impl BagRule {
fn can_contain(&self, color: &str, all_bags: &HashMap<String, BagRule>) -> bool {
if self.contains.iter().any(|(_, c)| c == color) {
return true;
}
self.contains.iter().any(|(_, c)| {
fn can_contain(
&self,
color: &str,
all_bags: &HashMap<String, BagRule>,
memoized: &mut HashMap<String, bool>,
) -> bool {
return match memoized.get(&self.color) {
Some(value) => *value,
None => {
let value = self.contains.iter().any(|(_, c)| c == color)
|| self.contains.iter().any(|(_, c)| {
// fetch rules for this bag in map
let bag_rule = &all_bags[c];
bag_rule.can_contain(color, all_bags)
})
bag_rule.can_contain(color, all_bags, memoized)
});
memoized.insert(self.color.clone(), value);
value
}
};
}
fn num_inner_bags(&self, all_bags: &HashMap<String, BagRule>) -> usize {